Effects of Surface Recrystallization on the Microstructures and Creep Properties of Single Crystal Superalloy DD6

2010 ◽  
Vol 638-642 ◽  
pp. 2279-2284
Author(s):  
Jia Rong Li ◽  
Feng Li Sun ◽  
Ji Chun Xiong ◽  
Shi Zhong Liu ◽  
Mei Han
Keyword(s):  
Single Crystal ◽  
Annealing Temperature ◽  
Low Cost ◽  
Rupture Life ◽  
Creep Rupture ◽  
Single Crystal Superalloy ◽  
Recrystallization Temperature ◽  
Creep Properties ◽  
Grit Blasting ◽  
Rupture Properties

This work assesses the effects of the surface recrystallization of the processing of water grit blasting, grit blasting and mechanically polishing on the microstructures and creep rupture properties of DD6 alloy, a low-cost second generation single crystal superalloy. The results demonstrate that the possibility and the depth of the surface recrystallization of DD6 show an increase as the annealing temperature increases from 1050°C to 1250°C. No surface recrystallization happens when the specimens of the alloy have been undergone at 1100°C for 4 hours after water grit blasting, but the surface recrystallization occurs at the annealing temperature above 1200°C for 4 hours after water grit blasting. The test indicates that the increasing pre-deformation decreases the surface recrystallization temperature. The creep rupture life of DD6 alloy without processing is 274.4 hours, 341.1 hours at the conditions of 980°C/250MPa, 1070°C/140MPa respectively. After annealing at 1100°C for 4 hours, the creep rupture life of the alloy with the processing of water grit blasting is equivalent to that of the alloy without processing. The surface recrystallization of the alloy happens with the processing of grit blasting after the annealing at 1100°C for 4 hours, and there is a reduction of the creep rupture life at the conditions as mentioned above. The creep properties of DD6 alloy meet the needs of blades and vanes of single crystal for advanced aeroengines when the surface recrystallization of the alloy occurs during manufacturing and processing.

Creep Properties and Microstructural Evolution at 760°C/785MPa of a Re-Containing Single Crystal Superalloy

2019 ◽  
Vol 944 ◽  
pp. 8-12
Author(s):  
Yun Song Zhao ◽  
Yan Fei Liu ◽  
Jing Xuan Zhao ◽  
Xiao Tie Zhang ◽  
Yan Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Single Crystal ◽  
Microstructural Evolution ◽  
Rupture Life ◽  
Turbine Blades ◽  
Creep Rupture ◽  
Single Crystal Superalloy ◽  
Creep Tests ◽  
Dislocation Configuration ◽  
Creep Properties

Intermediate temperature creep properties are considered a key indicator of single crystal superalloys used for turbine blades of aircraft engines. The interrupted and ruptured creep tests were carried out in a second generation single crystal superalloy under the conditions of 760°C/785MPa. The creep rupture life as well as minimum creep rate were also in the same level of those in CMSX-4 and PWA1484. The microstructural evolution at different creep stages were analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed the γ’ phases kept the cuboid morphology mostly until the creep rupture, and super lattice stacking faults (SSFs) extended along [-1 1 0] and [-1-1 0] orientations within the γ’ precipitate were the typical dislocation configuration.

Prediction of creep rupture life of a V-notched bar in DD6 Ni-based single crystal superalloy

2014 ◽  
Vol 615 ◽  
pp. 14-21 ◽  
Author(s):  
D.S. Liu ◽  
D.X. Zhang ◽  
J.W. Liang ◽  
Z.X. Wen ◽  
Z.F. Yue
Keyword(s):  
Single Crystal ◽  
Rupture Life ◽  
Creep Rupture ◽  
Single Crystal Superalloy

Effect of Squareness of Initial γ′ Precipitates on Creep-Rupture Life of a Ni-Base Single Crystal Superalloy at 760/982 °C

2018 ◽  
Vol 49 (7) ◽  
pp. 2929-2939
Author(s):  
Zhenbin Shi ◽  
Zhifang Peng ◽  
Yushi Luo ◽  
Hongji Xie ◽  
Haipeng Jin ◽  
...  
Keyword(s):  
Single Crystal ◽  
Rupture Life ◽  
Creep Rupture ◽  
Single Crystal Superalloy

scholarly journals Influence of normalizing and tempering temperatures on the creep properties of P92 steel

2020 ◽  
Vol 39 (1) ◽  
pp. 178-188
Author(s):  
Lakshmiprasad Maddi ◽  
Atul Ramesh Ballal ◽  
Dilip Ramkrishna Peshwe ◽  
M. D. Mathew
Keyword(s):  
Power Plants ◽  
Rupture Strength ◽  
Rupture Life ◽  
Creep Rupture ◽  
Laves Phases ◽  
P92 Steel ◽  
Creep Properties ◽  
Martensitic Microstructure ◽  
Actual Service ◽  
Rupture Properties

AbstractP92 steel is used as a piping material in ultra super critical power plants that can be operated at steam temperatures up to 650°C. The changes in the martensitic microstructure of P92 steel must be evaluated thoroughly before it is put into actual service. In this study, indigenously developed P92 steel was used. The steel was subjected to normalizing and tempering heat treatments in the range of 1,040–1,060°C and 740–780°C. The changes in the microstructure were evaluated and creep-rupture properties were studied at test temperatures of 600 and 650°C. Although normalizing temperatures influenced the microstructure and creep strength marginally, the change in tempering temperatures led to significant changes. The creep rupture strength at 600°C was influenced largely by the changes in the dislocation substructure, while the precipitation of Laves phases was a significant observation made for 650°C test temperature. Proposed mechanisms for the microstructural evolution and its consequences on the rupture life are discussed in this study.

Influence of Withdrawal Rate on Tensile and Stress Rupture Properties of the Single Crystal Superalloy DD9

2013 ◽  
Vol 747-748 ◽  
pp. 625-628 ◽  
Author(s):  
Z.X. Shi ◽  
J.R. Li ◽  
Shi Zhong Liu
Keyword(s):  
Single Crystal ◽  
Rupture Life ◽  
Stress Rupture ◽  
Single Crystal Superalloy ◽  
Withdrawal Rate ◽  
Stress Rupture Life ◽  
The Third ◽  
Stress Orientation ◽  
Stress Rupture Properties ◽  
Rupture Properties

The third generation single crystal superalloy DD9 was processed with different withdrawal rates and the effect of withdrawal rate on the tensile and stress rupture properties of the alloy was investigated. The relation between the mechanical properties and microstructure of the alloy with different withdrawal rates was discussed. The results showed that the withdrawal rate had a little effect on the tensile properties at 25 of the alloy. The tensile strength at 980 and stress rupture life at 1120/140MPa of DD9 alloy all increased with the increasing of withdrawal rate. The γ precipitates of specimen tensile at 25 had a little extension in the stress orientation. The extension of γ precipitates in the stress orientation at 980 was much more than that at 25. The vertical γ matrix at 980 became thinner and horizontal γ matrix became thicker slightly. The γ precipitates of those had rafted in a direction transverse to the applied stress.

Stress Rupture Properties of the Second Generation Single Crystal Superalloy DD6 after High Temperature Exposure

2007 ◽  
Vol 546-549 ◽  
pp. 1249-1252 ◽  
Author(s):  
Hai Peng Jin ◽  
Jia Rong Li ◽  
Shi Zhong Liu
Keyword(s):  
High Temperature ◽  
Single Crystal ◽  
Second Generation ◽  
Rupture Life ◽  
Stress Rupture ◽  
Single Crystal Superalloy ◽  
Stress Rupture Life ◽  
Stress Rupture Properties ◽  
Temperature Exposure ◽  
Rupture Properties

The effects of high temperature exposure simulating service conditions on stress rupture properties were studied for the second generation single crystal superalloy DD6. The specimens with [001] orientation were exposed in air at temperatures of 980°C and 1070°C for 100h to 1000h. They were then tested using conventional mechanical tests at 1070°C/140MPa to determine the effects of exposure on stress rupture properties. The analysis indicated that stress rupture life decreased with increasing exposure time. At the temperature of 980°C, the stress rupture life is more than 180h after exposure for 1000h. When the test temperature increased to 1070°C, the stress rupture life exceeds 100h after 800h exposure. The morphology of γ prime phase after exposure was observed by using scanning electron microscopy (SEM). Morphologies evaluations have shown that alloy DD6 exhibits excellent microstructure stability after exposure. TCP (Topologically Closed Packed) phases have not been observed. It has been also found that the morphology and size of γ prime affected stress rupture life of the alloy. The decrement in stress rupture life with increasing exposure is a result of γ prime rafting.

Effects of microstructure and lattice misfit on creep life of Ni-based single crystal superalloy during long-term thermal exposure

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Wenyan Gan ◽  
Hangshan Gao ◽  
Haiqing Pei ◽  
Zhixun Wen
Keyword(s):  
Single Crystal ◽  
Rupture Life ◽  
Precipitation Amount ◽  
Lattice Misfit ◽  
Thermal Exposure ◽  
Phase Evolution ◽  
Creep Rupture ◽  
Simultaneous Increase ◽  
Creep Life ◽  
The Matrix

Abstract According to the microstructural evolution during longterm thermal exposure at 1100 °C, the creep rupture life of Ni-based single crystal superalloys at 980 °C/270 MPa was evaluated. The microstructure was characterized by means of scanning electron microscopy, X-ray diffraction and related image processing methods. The size of γ’ precipitates and the precipitation amount of topologically close-packed increased with the increase in thermal exposure time, and coarsening of the γ’ precipitates led to the simultaneous increase of the matrix channel width. The relationship between the creep rupture life and the lattice misfit of γ/γ’, the coarsening of γ’ precipitate and the precipitation of TCP phase are systematically discussed. In addition, according to the correlation between γ’ phase evolution and creep characteristics during thermal exposure, a physical model is established to predict the remaining creep life.

Sign in / Sign up

Export Citation Format

Share Document